Implemented /metrics endpoint and reimplemented /stats

closes #418 (/metrics endpoint)

Usage:
```yaml
scrape_configs:
  - job_name: 'engelsystem'
    static_configs:
    - targets: ['engelsystem.example.com:80']
```

1 files changed, 0 insertions, 47 deletions

diff --git a/includes/pages/guest_stats.php b/includes/pages/guest_stats.php
deleted file mode 100644
index d9012748..00000000
--- a/includes/pages/guest_stats.php
+++ /dev/null
@@ -1,47 +0,0 @@
-<?php
-
-use Engelsystem\Database\DB;
-use Engelsystem\Models\User\State;
-use Engelsystem\Models\User\User;
-
-function guest_stats()
-{
-    $apiKey = config('api_key');
-    $request = request();
-
-    if ($request->has('api_key')) {
-        if (!empty($apiKey) && $request->input('api_key') == $apiKey) {
-            $stats = [];
-
-            $stats['user_count'] = User::all()->count();
-            $stats['arrived_user_count'] = State::whereArrived(true)->count();
-
-            $done_shifts_seconds = DB::selectOne('
-                SELECT SUM(`Shifts`.`end` - `Shifts`.`start`)
-                FROM `ShiftEntry`
-                JOIN `Shifts` USING (`SID`)
-                WHERE `Shifts`.`end` < UNIX_TIMESTAMP()
-            ');
-            $done_shifts_seconds = (int)array_shift($done_shifts_seconds);
-            $stats['done_work_hours'] = round($done_shifts_seconds / (60 * 60), 0);
-
-            $users_in_action = DB::select('
-                SELECT `Shifts`.`start`, `Shifts`.`end`
-                FROM `ShiftEntry`
-                JOIN `Shifts` ON `Shifts`.`SID`=`ShiftEntry`.`SID`
-                WHERE UNIX_TIMESTAMP() BETWEEN `Shifts`.`start` AND `Shifts`.`end`
-            ');
-            $stats['users_in_action'] = count($users_in_action);
-
-            header('Content-Type: application/json');
-            raw_output(json_encode($stats));
-            return;
-        }
-        raw_output(json_encode([
-            'error' => 'Wrong api_key.'
-        ]));
-    }
-    raw_output(json_encode([
-        'error' => 'Missing parameter api_key.'
-    ]));
-}